High or low fluid flow signalling apparatus



p 1969 R. G. TAYLOR, JR

HIGH OR LOW FLUID FLOW SIGNALLING APPARATUS Filed June 18, 1968 4Sheets-Sheet 1 INVENTOR. E4 VMOA/D 721M402, J5 ZJ A Tram/6V lfi- 1969 R.G. TAYLOR. JR

HIGH OR LOW FLUID FLOW SIGNALLING APPARATUS Filed June 18, 1968 4Sheets-Sheet 2 9 w w V??? 31 mm.

I NVENTOR. B4VMO/V0 6. 720 402, Je

BY g 1 ATTOEA/EV p 23, 1969 R. G. TAYLOR, JR 3,468,035

HIGH OR LOW FLUID FLOW SIGNALLING APPARATUS Filed June 18, 1968 4Sheets-Sheet 5 IN VENTOR- eaymw a. mmaJe Sept. 23, 1969 TAYLOR, JR3,468,035

HIGH OR LOW FLUID FLOW SIGNALLING APPARATUS Filed June 18, 1968 4Sheets-Sheet 4 //0 4&4

/7& 7 INVENTOR.

, EA VMO/VD 6. W402, JZ

BY "1' 27.6 7 /7e Unite US. Cl. 33-205 9 Claims ABSTRACT OF THEDISCLOSURE Signalling apparatus for producing pressure pulses in thestream of well drilling fluid in which the fluid flows through a pulsering assembly having axially spaced rings cooperative with a knobreciprocable through said rings to provide restricted flow pathsproductive of the fluid pressure pulses in the drilling fluid stream ina number representative of the disposition of the well drilling stringin the Well bore in the vicinity of the drill bit, and in which areplaceable flow bushing is employed to provide a selected flow areabetween the pulse ring and the knob when the knob is in its normalposition responsive to the influence of drilling fluid pressure thereon,so that movement of the knob to said position is assured under theprevailing flow rate. Such apparatus in which a gravity responsivependulum system is utilized to determine the extent of movement of saidknob and releasable latch means connect the gravity responsive means tothe knob.

Background of the invention In general, signalling drift indicators ofthe type here involved are adapted to be disposed in a drill collar subabove the drill bit of a well drilling string. The instrument includesan elongated housing containing clean oil, and internal pressure isbalanced with external pressure by a floating divider at the lower endof the instrument. At the upper end of the housing is a pulse ringattachment through which drilling fluid flows during drilling.Reciprocable in the upper end of the housing is a shaft having a knobwhich passes upwardly through the pulse rings upon extension of theshaft from the housing and which responsive to flow of drilling fluidwill force the shaft downward within the housing. As the knob passesdownward through the pulse rings it cooperates with them to providerestrictions to flow. Such movement is retarded so that the successiverestrictions cause distinct pressure pulses which will travel throughthe column of fluid to the earths surface, where the signals may berecorded. Gravity responsive means are provided in the housing forlimiting shaft extension in accordance with the angle from vertical atwhich the housing is disposed when the circulation of drilling fluid ishalted. Thus, the pressure pulses recorded at the surface are indicativeof the angle of the well in the region of the drill string sub in whichthe instrument housing is installed.

Such apparatus may include a coding system including a rod, stop membersselectively expandable by the rod, and a stop carried by the shaft andengageable with the expanded stop members. The coding rod is controlledby the gravity responsive means so that the ultimate travel of the shaftand thus the knob through the pulse rings is directly related to theangle of the instrument. Such an instrument therefore produces a pulsefor each increment of the total angle which the instrument may measure.

In the use of such apparatus it has been determined that it is desirableto disconnect the gravity responsive means from the shaft which supportsthe pulse knob after the gravity responsive means has performed its stopfunc- States Patent tion, whereby to protect the gravity responsivemeans against undue wear or destruction.

An apparatus typical of that generally described above is illustratedand described in the application for United States Letters Patent filedby Robert L. Alder on July 1, 1966, Ser. No. 562,146.

One of the difliculties encountered in the utilization of such apparatusis the fact that the force relied upon to move the pulse producing knobdownwardly to its lowermost position during the drilling operations isderived from the effect of drilling fluid pressure upon the knob; butinasmuch as different wells are drilled at different drilling fluid flowrates, the pressure differential across the pulse knob is not always thesame. However, the flow restriction productive of the differentialpressure across the knob has been uniform in the signalling devices andso also has the internal forces within the apparatus tending to resistthe downward movement of the knob. Accordingly, in some instances thepressure acting upon the knob to move the same downwardly isinsufficient to overcome the forces tending to resist such downwardmovement, resulting in the fact that the knob supporting shaft mayproject upwardly from the instrument housing and be subjected to theerosive action of the drilling fluid on surfaces which are required toeffectively cooperate with sealing means to prevent instrusion ofdrilling fluid into the instrument housing. Other problems exist inrespect of the means for releasing the gravity responsive means from theknob supporting shaft inasmuch as, in order for such releasing means tobe reconnected, it is necessary that the shaft in response to fluidpressure acting on the knob move fully to its lowermost postion; and, ifthe knob is not in its lowermost position when the circulation ofdrilling fluid is interrupted to permit upward travel of the knob, thenerroneous indications of the angular disposition of the drill string maybe produced when the circulation of drilling fluid is resumed.

Summary With the foregoing in mind, the present invention providesapparatus for producing signals in the stream of drilling fluid in whicha pressure responsive knob is normally held in a lowermost position bythe flow of drilling fluid but is movable upwardly through pulse ringswhen the flow of drilling fluid is interrupted so that, upon resumptionof drilling fluid flow, pressure pulses will be produced in the fluidstream indicative of the disposition of the instrument within the wellbore, wherein the apparatus may be pre-conditioned for operation in thedrilling of wells over a wide range of drilling fluid flow rates whileassuring that the knob will be subjected to suflicient pressure by thedrilling fluid stream to cause its downward movement to the limit of itspermitted downward travel.

More specifically, the apparatus is adapted to be preconditioned so asto assure downward movement of the knob and resultant connection ofreleasable connector means which are adapted to connect the gravityresponsive means to the mechanism which controls the upward movement ofthe knob.

In accomplishing the foregoing, the present invention provides areplaceable bushing having an opening therethrough for the reception ofthe pulse producing knob of the apparatus, whereby the flow area betweenthe bush ing and the knob can be preselected so as to cause theproduction of suflicient pressure diiferential across the knob undergiven fluid flow conditions so as to assure that the knob will be forcedto its lowermost position. As results of the fact that the knob will beforced to its lowermost position, the knob supporting shaft is protectedagainst the erosive action of the drilling fluid and releasableconnector means in the instrument are effectively reconnected. Thebushing is composed of wear-resistant material so as to minimize theeffects of fluid erosion.

Other advantages and objects of the invention will be hereinafterdescribed or will become apparent to those skilled in the art, and thenovel features of the invention will be defined in the appended claims.

Brief description of the drawings FIG. 1 is a fragmentary view partly invertical section and with certain parts shown in elevation, illustratinga drift indicator instrument installed in a drill collar sub, the shaftbeing in its down position and the pendulum being on its seat;

FIG. 2a is an enlarged fragmentary detail view in longitudinal sectionshowing the upper end of the instrument of FIG. 1, minus the pulse ringassembly, and showing the upper portion of the coding system;

FIG. 2b is a downward extension of FIG. 20. showing the upper actuatingmeans for the angle adjuster and showing the intermediate portion of thecoding system;

FIG. 2c is a downward extension of FIG. 21), showing the lower portionof the angle adjuster, and showing the lower portion of the codingsystem including the pendulum release means;

FIG. 2d is .a downward extension of FIG. 20, showing the pendulum seat,with the pendulum seated thereon, and showing the lower instrumentsupport and the internal-external pressure balancing divider and theinstrument fluid transfer restrictor and bypass;

FIG. 3 is an enlarged fragmentary view in vertical section showing thependulum release system, with the pendulum connecting rod connected tothe coding rod and in the extreme upper position just prior to release;

FIG. 4 is a fragmentary view in vertical section corresponding to FIG.3, but showing the pendulum connecting rod released and urged downward,as compared to FIG. 3, to allow reseating of the pendulum, and showing,in broken lines, the pendulum release means moved downward forreconnection with the connecting rod;

FIG. 5 is a view taken on the line 5-5 of FIG. 3;

FIG. 6 is a view taken on the line 6-6 of FIG. 4; and

FIG. 7 is an enlarged fragmentary view in longitudinal sectionillustrating the pulse tube mounting and the replaceable bushing of theinvention.

Description of the preferred embodiment Referring to FIG. 1, it will beseen that the drift indicator assembly of the invention is installed ina sub or length of drill collar S which is, as customary, adapted to bemounted in a string of drill pipe so as to conduct drilling fluiddownwardly through the drill collar sub S to the bit, not shown, and thefluid then flowing upwardly outside of the drill string to the earthssurface. This assembly comprises an instrument housing generally denotedI having at its upper end a pulse ring sleeve R and at its lower end abottom support B whereby the housing I is supported top and bottom inthe sub S, and drilling fluid may flow through the sub S about thehousing I.

The pulse ring sleeve R has an enlarged end flange 2 which shoulders andis sealed in a seat 3. At its lower end (FIG. 7) the pulse ring sleeve Rhas an outwardly extended flange 5a which seats upon the upper end of acylindrical support 5 which is connected to a central hub 4 and provideswindows 6 so that fluid may pass through the sleeve R. The hub 4 issuitably mounted on the upper end of the instrument I so as to supportthe pulse ring sleeve R thereabove, this mounting being preferably likethat more specifically described in the application for United StatesLetters Patent, Ser. No. 561,637, filed June 29, 1966. The flange 5a ofthe pulse ring sleeve R is removably connected to the tubular member 5by suitable means, such as fasteners Sb. Within the cylindrical member 5is a bore 50 providing an inwardly projecting shoulder 5d, this shoulder5d and the lower end 5c of the pulse ring sleeve R defining an annularspace for reception of a replaceable bushing A. This bushing A may besuitably hardened or composed of erosion-resistant material so that itsinner cylindrical wall 5 is resistant to the erosive effects of drillingfluid flowing therepast. At its lower end the bushing A is provided witha downwardly extended lip 5g having an outwardly flaring or beveledsurface 5h leading into the cylindrical member 5. Within the sleeve R isa series of axially spaced pulse rings 7, each of which is adapted tocause a pressure pulse in the fluid stream passing therethrough, as willhereinafter appear. Between the rings 7 are axially extended andangularly spaced ribs 8 forming abutments in the spaces between theribs, these abutments extending substantially to the inner annularsurfaces of the rings 7 from the circumferentially extended walls 8abetween the pulse rings 7. The diametrical distance between the walls 8ais, in the illustrative embodiment, greater than the diameter of thecylindrical wall 5f of the bushing A for reasons which will hereinafterbecome apparent, but the wall 5] has a selected diameter which in somecases may be substantially equal to the diameter of walls 8a.

Bottom support B has an outer rim 9 and a hub 10 on which the rim 9 issupported by webs 11 forming therebetween flow passages at the lower endof housing I. A port 12 is provided in the hub 10 so that fluid findsaccess to the housing I at its lower end.

The housing at its upper end has reciprocably mounted thereon andextensible therefrom a shaft 13 having at its outer extremity a head orknob 14. Within housing -I is a spring 15 which normally biases shaft 13upwardly out of the housing '1, thereby causing the head 14 to be movedupwardly through the pulse rings 7. However, the flow of drilling fluiddownwardly through the pulse ring sleeve R will cause the head 14 tomove downwardly, and the flow of fluid downwardly through the annularspace St between the knob and the bushing A will provide a pressuredifferential acting on the knob 14 to hold the same in its lowermostposition in abutting engagement with the upper end of the instrument I.Thus, during circulation of drilling fluid the shaft 13 and knob 14 willremain as shown in FIG. 1, but when such circulation is halted, theshaft will be forced outward and the head will move upward through therings 7. Such circulation of drilling fluid is automatically ceased eachtime an additional length of drill pipe is to be added at the earthssurface, and otherwise as desired. \Vhen circulation is resumed, apressure pulse is caused as the knob 14 passes through the rings 7 dueto the restriction in flow area, and such pulses are detectable at theearths surface by a typical pressure gauge or pressure recorder.

In order that the upward movement of the shaft 13 will be limited inaccordance with the angle at which the housing I is disposed, gravityresponsive means including a pendulum generally denoted at 16 is adaptedto selectively engage pendulum stop means 17 as the pendulum movesupwardly. In order to retard downward movement of the shaft 13 so that,as previously indicated, the resultant pressure pulses will be distinctand adequately spaced, means generally indicated at 18 are provided forretarding fluid displacement through the pendulum seat 19. At the lowerend of the housing I is a divider piston 20 shiftable to balanceinternal fluid pressure and external drilling fluid pressure and so asto enable the transfer of fluid through the retarding means 18 as theshaft 13 displaces fluid downwardly and the upward transfer of fluidthrough a check valve 22 as the shaft 13 is urged upwardly.

In order to change the relationship between the stop means 17 and thependulum 16, means are provided for shifting the stop means axially inhousing I. In this connection the stop means 17 is connected by rods 23to adjuster means 24.

Referring now more particularly to FIGS. 2a through 2d, the details ofthe structure will be more fully explained.

The instrument housing I includes an upper tubular section having anupper shaft guide 31 threadedly mounted therein. Shaft guide 31 has aseal and wiper means 32 and 33, respectively, engageable with the shaft.At the outer extremity of the shaft, the knob 14 is supported by meansof a knob bushing 34, a pin 35 connecting the bushing to the shaft, anda snap ring 36 retaining the knob on the bushing.

As seen in FIG. 20, the upper housing section 30 is threaded to a lowerhousing section 37 to the lower end of which is connected the hub 11 ofbottom support B, as shown in FIG. 2d. Within the lower housing sectionis the divider piston 20 which has a skirt 38 adapted to extend into thehub 10. Mounted in the skirt 38 is a hollow piston guide stem 40, at thelower end of which is a filler plug 41, whereby the housing may befilled with clean oil or the like. A spring 42 seated in hub 16 isprovided to normally bias the piston 21} upward, but essentially thepiston 20 serves to apply pressure to the internal fluid equal toexternal fluid pressure and to move axially to allow extension of theshaft 13 from the housing.

Disposed above the piston 20 in lower housing section 37 is an orificeblock 43, retained in place by a lock ring 44 and having a downwardlyextended guide tube 45 slidably receiving the piston guide stem of thepiston. Supported by an upwardly extended tubular part 46 on the block43 and within guide tube is an orifice disc support 47 having therein astack of orifice discs 48 retained in place by a ported plug 49. At oneside of block 43 is an upwardly opening ball check valve 22 and atanother location in the block 43 is a downwardly opening spring loadedrelief valve 50. Thus, the orifice block, the valve 22 and the orificediscs 18 constitute means for retarding downward flow of housing fluidthrough the block 43, while enabling comparatively free upward flow ofhousing fluid, as the shaft is extended from the housing and forced backinto the housing during operation of the instrument. The valve 50 servesto relieve pressure in the event that such relief may be necessary.

The block 43 also supports the aforementioned pendulum seat 19. Thisseat 19 comprises a conical center 51 having an upstanding guide skirt52. The seat center has a ported stem 53 and means are provided foradjustably supporting the stem 53 and hence the seat 19 within the upperend of block part 46. Such means in the illustrative embodiment comprisea spider 54 in which the stem 53 is threaded, and a lock 55 engageablewith the spider.

The pendulum 16, as shown in FIG. 2d, is adapted to seat in the pendulumseat 19 when, as shown in FIG. 2a, the shaft 13 is in the downwardposition. The shaft is connected to the pendulum by means which (1)allow upward movement of the shaft a distance inversely related to theupward travel of the pendulum, and (2) by means which, upon the pendulumreaching the upper l1m1t of ts travel, will cause release of thependulum so that it Wlll be freed to return to its seat.

The first-mentioned means includes a longitudinally extended coding rodwhich is reciprocally disposed 1n a tubular guide and stop ball support61. The guide 61 is connected to and essentially constitutes a portionof the upper housing section 30, and, as best seen in FIG. 20, the guideis supported at its lower end in a coding rod stop tube 62 which isformed as an upward extension of a block 63 which in turn is secured asby fasteners 64 to the lower end of the upper housing section 30. Morespecifically, the guide 61 seats at its lower end on a washer 65 whichshoulders at 66 in the upper end of the tube 62; and, in upwardly spacedrelation to the washer 65, is a second washer 67 fastened in the tube 62by lock ring 68, the lower end of the guide 61 extending through washer67 and having a lock ring 69 which engages beneath the washer 67. Thusit is apparent that while the guide 61 is assembled with the tube 62prior to connection of the block 63 to the lower end of housing section30, means are provided so that the ultimate assembling of thesecomponents results in the guide 61 being rigidly and concentricallysupported within the upper housing section 30.

The coding rod 60 previously referred to is composed of an upper endsection 70 slidably disposed within the guide 61. Beneath the upper end70 is an axially spaced series of reduced stem sections 71 and thimbles72a, 72b, 72c, 72d, 722 and 72 Beneath the lowermost thimble 72 is aconnector 73 which connects the upper coding rod section 74, the latterextending downwardly through the guide 61 and the guide supportingwashers 65 and 67 into the coding rod stop tube 62. At its upper end,coding rod section 70 has a centralizing guide 70a secured thereto andslidably engaged in the shaft 13, this guide being perforated to permitbypass of fluid within the instrument. Above the guide 70a is a coilspring 70b freely disposed in shaft 13 so as to engage and bias thecoding rod downward when the shaft is in its downward position, as shownin FIG. 2a. As shown in FIGS. 2!; and 2c, there is another coi lspring60a which surrounds the lower coding rod section 74 within rod guide 61and engages at its upper end with connector 73 and at its lower end withthe support washer 65 for tube 62. This spring 60a is adapted tonormally bias the coding rod 60 upward when the shaft 13 moves upwardly.It is the purpose of the thimbles 72a-72f depending upon the extent ofupward movement of the coding rod, as will be more fully explainedhereinafter, to selectively hold in an outwardly projected position aset of stop projections which more specifically are composed of sets ofballs. In the illustrative embodiment, there are 6 sets of such ballsrespectively designated from top to bottom, as viewed in FIGS. 2:: and2b, 75a, 75b, 75c, 75d, 75e and 75 adapted to be moved outward bythimbles 7241-72 respectively. The balls are disposed in openings 76 inthe rod guide 61 so that the latter also constitutes a ball support. Thesets of balls are cammed outward upon engagement by the respectivethimbles 72a-72f into annular space 13a defined by the guide 61 and theshaft 13. Within the shaft 13 (see FIG. 2b) is a stop 77 which definesthe bottom of the just-mentioned annular space 13a, and essentially thisstop forms a portion of the shaft 13 which will limit upward movement ofthe latter, under the influence of spring 15, upon engagement with oneof the sets of stop balls 75a75f, or upon engagement with a stop ring 75carried by tube 61 in spaced relation above stop balls 75a (FIG. 2a),thus selectively limiting upward movement of the knob 14 with respect tothe pulse ring sleeve R.

Essentially the stop shoulder 77 is a portion of the shaft 13, but inthe specifically shown structure the shaft 13 incorporates means forallowing freedom of upward movement of the shaft independently of thestop shoulder '77 in order to relieve the stop shoulder and stop ballsfrom excessive loading in the event of back flow of drilling fluidthrough the drill collar S, as well as during running of the drillstring into the well bore following the changing of drill bits.Accordingly, as shown in FIGS. 2b and 2c, the shaft 13 is reduced indiameter at the point of its connection with a downwardly extended shaftextension 80. If desired, the shaft 13 may be provided with an enlargedsleeve 80a above the shaft extension 86 to stablize the shaft assemblyWithin the body section 311. Concentrically disposed about the downwardshaft extension 80 is a spring coupling sleeve 81 having an upperoutwardly projecting flange 82 engaged by the upper end of a shaftbiasing spring 15. The lower end of the latter abutting, as shown inFIG. 20, with the block 63. The just-mentioned flange 82 also abuts withthe larger diameter upper shaft section so that the shaft 13 is biasedupwardly. At its lower end the spring coupling sleeve 81, as seen inFIG. 2c, is connected between a pair of snap rings 84 with an internalsleeve 85 which is disposed within the downward shaft extension 80. Thusit will be seen that the shaft extension 80 is free to move upwardlyrelative to the spring coupling sleeve 81 and the connected internalsleeve 85, but the spring 15 acts to bias the shaft 13 upwardly throughthe intermediary of the spring coupling sleeve 81 and internal sleeve85, the latter having at its upward extremity the above-mentioned stopshoulder 77. Therefore, the extent of upward movement of the shaft 13and the knob 14 under the influence of the spring 15 is limited by thestop 77, even though the shaft may be free to move further upwardly inresponse to the influence of fluid flow through the drill collar S.

Thus it will be apparent that if the balls 75 be cammed into the path ofstop 77, the shaft 13 will be limited in its upward travel under theinfluence of spring 15 to a position at which the knob 14 is disposedbetween the lowermost and the next above pulse ring 7. As the shaft 13is allowed further increments of upward movement then the knob 14 willcorrespondingly be allowed further upward movement, a distance equal toanother pulse ring per increment of shaft movement. Thus if the stop 77is allowed to pass all the sets of stop balls 75 through 75a but engagesstop ring 75, the knob 14 will be allowed to travel a distance equal tothe spaces between 7 pulse rings as a results of which downward movementof the knob caused by drilling fluid flow will cause the production of 7pressure pulses or signals which will travel through the column ofdrilling fluid to the earths surface for detection or recordation as anindication of the angle at which the housing 30 is disposed Within thewell bore. As previously described, the gravity responsive pendulum andthe cooperative pendulum stop means 17 serve to limit upward movement ofthe coding rod do so as to cause the projection of the appropriate setof stop balls 75a through 75 to limit upward movement of shaft 13.However, as mentioned above in accordance with one of the objectives ofthe invention, shaft 13 is releasably connected to the pendulum as willnow be described and as is more particularly illustrated in FIGS. 20, 3and 4.

In prior instruments of the type here involved, and more particularly ininstruments as specifically shown in Letters Patent of the United StatesNo. 3,176,407, the gravity responsive pendulum is directly connected tothe coding rod. In the present construction, however, the coding rod 60is releasably connected to the pendulum 16 so that the shaft 13 is alsoreleasably connected to the pendulum.

Slidably disposed within the coding rod stop tube 62 and within theblock 63 is a connecting rod 90, to the lower end of which the pendulumis freely universally connected as by a pair of bails 91. At its upperend the connecting rod 9% is provided with a seat 92 formed within acup-like female connector member 93 which has at its upper end a latchshoulder 94. Releasably engaged in the seat 92 is a latch mechanismcomprising a body 95 having a reduced head 96 disposed in the seat 92and within the latch shoulder 94 of the latter. Pivotally supported bythe body 95 is a dog 97 having a latch finger 98 which is biased byspring 99 outwardly into latching engagement with the shoulder 94. Thedog 97 also comprises a stop finger 100 having a laterally outwardlyprojecting end 191 which, when the latch finger 98 is engaged with theshoulder 94, as seen in FIG. 20, is held in a retracted position withina slot in the body 95 in which the dog is pivotally mounted. The finger100 of the dog also has an inward projection 102 beneath which isengaged an annular flange 193, which is, in the illustrative structure,provided on a thimble 104 suitably secured to the lower end of thecoding rod 60. The thimble 194 is disposed within a bore 105 in thelatch body 95 so as to enable limited relative upward movement of thecoding rod, such upward movement being limited by a flange 106 on thethimble and a snap ring 107 within the bore of the body. Beneath thebody 95 and projecting downwardly from the head 96 is a stem 108. Thisstem extends into a bore in the connecting rod 90 and is surrounded by aspring 110 seated in the bore 109 and providing a force normally tendingto separate the latch body from the connecting rod. The force of thespring 110 combined with the friction of the latching finger 98 with thelatching shoulder 94 provide a holding force which must be overcome bythe tendency of the coding rod 60 to move upwardly beyond a point atwhich upward movement of the connecting rod is arrested. Such a forcetending to move the coding rod upwardly is provided by the coding rodactuator spring 60a previously described.

In accordance with the present invention, the coding rod 66 is to bereleased from the pendulum connecting rod 99 when the coding rod hasreached the limit of the desired upward travel, that is, a location atwhich one or another of the sets of locking balls 750-75 have beendisplaced outwardly by thimbles 7211-727 so as to preclude movement ofshaft stop 77 upwardly beyond the outwardly projecting stop balls, orwhen the thimbles are so disposed that none of the stop balls areprojected and shaft stop 77 will pass all of the balls and engage stopring 75. Thus, means are provided to cooperate with the latch mechanismwhen the connecting rod 93 is released to limit further upward movementof the coding rod ea. In the illustrative embodiment, the coding rodstop tube 62 is provided with a vertically spaced series of stops 175,175a, 175b, 1750, 175d, 1752 and 175 which are respectively adapted tobe engaged by the outward projection 191 on the stop finger 1th of thedog 97, when the latter is cammed outwardly by the thimble 104responsive to further upward movement of the coding rod 6%) after upwardmovement of the latch body 95 has been arrested either by engagement ofthe pendulum 16 with the pendulum stop means 17 or upon engagement ofthe latch body 95 with the washer 65 adjacent the top of the coding rodstop tube 62. Stops 175-175f are provided by forming recesses inalignment in the stop tube 62. Means are provided to maintain alignmentof the dog 97 with the recesses, and such means may comprise a pin 94aon latch member 95 slidable in an elongated keyway 94b in stop tube 62(FIG. 6).

It will be noted that the spacing of axial stop balls 75a75f relative tothe thimbles 72n72f, as shown in FIGS. 2a and 2b, is such that none ofthe stop balls will be projected outwardly into the path of shaft stop77 when the coding rod has traveled upwardly the minimum extent, but thelatch balls 75 will be projected outwardly into the path of stop 77 whenthe coding rod has traveled upwardly to the maximum extent, that is,when the latch body 95 abuts with the washer 65 as previously described.As a result, the shaft will be allowed to move upwardly a minimum extentwhen balls 75 are projected outwardly and a maximum extent when none ofthe balls are projected outwardly. This inverse relationship as justdescribed results in a direct relationship between the angle at whichthe housing is disposed relative to the gravity responsive pendulum whenthe upward motion of the pendulum is arrested and the extent of upwardtravel of shaft 13. More particularly, there is a resultant directrelationship between the number of pulse rings through which the knob 14will pass upwardly and the number of pressure signals produced when theknob is forced downwardly by the flow of drilling fluid and the angle atwhich the housing I is disposed. Therefore, in respect of each incrementof angular deviation there will be produced one pressure signal, and ina manner which will be hereinafter described, the range of angulardeviation at which the instrument will respond may be adjusted so thatthe sensed deviation may be, for example, in increments of /2 degreeranging from 0 to 3 /2 degrees in the illustrative embodiment or inincrements of /2 degree ranging from 3% degrees to 7 degrees, etc.

Referring now to FIG. 3, it will be noted that connecting rod and thelatch mechanism comprising the member 94 and body have been moved fromthe position shown in FIG. 20 to the upward permissible limit of travelof the latch body 95, as would occur upon cessation of the circulationol drilling fluid downwardly through the drill string. Such upwardmovement, it will noW be under stood, will be caused by the forceexerted by spring 15 upon the spring coupling sleeve 81 (FIG. 2b) whichhas caused the shaft 13 to move upwardly and the force applied by spring60a to move the coding rod 60 upwardly (FIG. 2b). It will now also beunderstood that the gravity responsive means comprising the pendulum 16and the pendulum stop means 17 will permit the illustrated upwardmovement of the latch body 95 by reason of the fact that the instrumenthousing I is in essentially a vertical disposition, in the event thatthe instrument is set to detect angular deviation in the range of to 3/2 degrees as just-mentioned above. Under these circumstances, the upperend of body 95 will abut with washer 65 to limit further upward movementof the inter-connected latch body and connecting rod 90. At this point,however, the coding rod biasing spring 60a will cause further upwardmovement of the coding rod 66. As a result, the flange 103 on thimble104 will exert an outward camming action on the inward projection 102 offinger 100 on the dog 97. Thus, the latch finger 98 of the dog will bereleased from the latch shoulder 94 and the outward projection 1131 ofdog finger 190 will be displaced into the recess 175 Two things occurunder the conditions just described, namely (1) responsive to therelease of the latching finger 98 from shoulder 94, spring 119 will biasthe connecting rod 90 downwardly from the position shown in FIG. 3 tothat shown in FIG. 4, and (2) further upward movement of the coding rod66 will be prevented by engagement of the outward projection 161 in therecess 175 combined with engagement of flange 166 on thimble 1.94 withsnap ring 107 carried within the bore 105 of the latch body 95.Therefore, in accordance with one of the objectives of the invention,the relationship between the coding rod 61) and the stop shoulder 77 onthe shaft is established, and, simultaneously, the connecting rod 91 isreleased so that the pendulum 16 is permitted to move downwardly intoengagement with the seat 19. By virtue of the structure just describedwhich permits the release of the pendulum from the coding rod, thependulum 16 and stop means 17 hereinafter to be more specificallydescribed are protected against damaging impact loadings and resultantwear which has been found in the operation of conventional instrumentsto result in inaccurate readings of angular deviation. Furthermore, itwill now be understood that the bails 91, in order to enable freependulum movement, must be delicate as compared with the pendulum 16 andthe stop means 17, and the release of the pendulum 16 from the codingrod also reduces the load applied to the bails tending to deform thesame. The releasing operation just described, resulting from engagementof the latch body 95 with washer 65, will also occur in the event thatthe pendulum 16 is stopped by the stop means 17 at any selected lowerlocation, the significant point being that the upward movement of thelatch body 95 is arrested so that a further slight movement upward ofthe coding rod 69 will effect camming outwardly of the stop finger 100of the dog 97, and, as previously described, the pendulum 16 is adaptedto engage the stop means 17 at spaced locations as a function of thedeviation of the instrument housing I from vertical.

In any event, following release of the pendulum from the coding rod,resumption of the circulation of drilling fluid downwardly through thedrill collar S, which results in downward movement of knob 14 and shaft13, will cause re-engagement of the releasable latch means so that theconnecting rod 99 will again be connected by dog 97 to the latch body95. Thus, as shown in broken lines in FIG. 4, the coding rod 60 will bemoved downwardly to the extent that the thimble 1 in the bore 105 willforce the latch body 95 downwardly against spring 110. Under thesecircumstances, the inward projection 102 of finger 198 of the dog 97will be freed to move inwardly into the reduced section of thimble 164lying between the flange 196 and flange 103. As a result, the

latch body will be freed for downward movement to the position shown inbroken lines in FIG. 4, at which the latch finger 98 will be cammedinwardly by the latch shoulder 94 so that the finger 98 will pass overthe shoulder 94 to be re-engaged with the latter. For the purpose ofpermitting the camming action of shoulder 94- on the latch finger 98,the coding rod stop tube 62 is provided with an elongated slot 62aaligned with recesses 175175f, into which the outward projection offinger on dog 97 may extend during the just-mentioned camming action.The slot 62a is elongated so as to allow for tolerance in themanufacture of components. As previously indicated, in accordance withone of the features of the present invention, means are provided foradjusting the bail connection between the connecting rod 90 and pendulum16, thus, as best seen in FIG. 3, the bails comprising an upper bailwire 91a and a lower bail wire 91b, each formed to provide a loopcoengaged with the other. The bail 91a is mounted in a support 191awhich extends into a bore 192a in the lower end of the connecting rod90. The support 191a has at its inner end a threaded stem 192a foradjustably positioning the support 191a in the bore 192a. Support 191ais provided with a pair of diametrical openings, one of which is shownat 194a and into which a suitable tool may be inserted so as to deformthe bail Wire to prevent its removal from the support 191a. The positionin which the support 191a is to be fixed may be determined and fixed byinsertion of a suitable locking element such as a cotter pin 195a or thelike. In a similar fashion, the bail 91b is mounted in the support 1911)and the support 1911) is provided with openings 19412 to enabledeformation of the bail to prevent its removal from the support 19112.In addition, this latter support has a threaded end 1913b engaged in thependulum 16 so as to adjust the position of support relative to thependulum 16. As in the case of support 191a, support 1911) may be fixedin adjusted position by a cotter pin 195b which extends through thesupport 1911). By virtue of this adjustable pendulum supportingstructure, the relationship of the pendulum 16 to the connecting rod 90may be adjusted to maintain a stable but substantially friction-freeuniversal connection between the connecting rod 91) and the pendulum 16so that the pendulum 16 may freely swing relative to the connecting rod90 to any desired angular disposition relative to the stop means 17 andso that upward movement of the pendulum 16 will be arrested at a preciseposition representative of the angular disposition of the housing I.

It will be noted, as seen in FIGS. 1, 2c and 20', that the stop means 17comprises a supporting sleeve 17a connected to the above-describedadjuster rods 23 by means of pins 17b. Adjacent the bottom of sleeve 17ais a stop ring retainer held in place by a snap ring 17d. Intermediatethe retainer 170 and the upper end of the sleeve 17a is a series ofangular stop shoulders of progressively diminishing diameter. Preferablysuch shoulders are provided on a series of stacked stop rings 17c. Inthe illustrative embodiment there is an upper stop shoulder 275a (FIG.20) provided by the uppermost stop ring 17a and progressing downwardlyare stop shoulders 275d, 2750, 275b, 275a and 275 of progressivelyincreasing diameter. Thus, if upper movement of the pendulum 16 isarrested by stop shoulder 2752, outward projection 101 of dog 97 willengage with the stop at 175.2 in coding rod stop tube 62 and balls 75e(FIG. 2a) will be caused to project into the path of stop 77 (FIG. 2b)of the shaft 13. The same relationship exists between each of the stopshoulders 275 through 275d, dog stops through 175d and stop ring 75 andballs 75a through 75d so that, while the upward travel of the pendulum16 will be inversely related to the angular deviation of the instrumenthousing I, the permitted upward travel of the coding rod 60 and hencethe permitted upward travel of the shaft 13 will be directly related tothe angular deviation of the housing I from a vertical disposition, anda single pressure signal will be induced in the drilling fluid streamfor each increment of angular deviation.

As indicated above, the range of angular deviation at which theinstrument may respond is adjustable in response to rotation of thehousing part 24 relative to the upper housing 3% whereby to axiallyshift stop ring supporting sleeve 17a relative to the pendulum 16. Asseen in FIGS. 2b and 2c, the housing part 24 is provided with aninternal thread 24a. This internal thread 24a engages in a helicalgroove 24b in a connector sleeve 24c disposed within part 24 andslidably mounted on the upper housing section 3%. Referring to FIG. 20,it will be noted that the sleeve 240 is connected by means of a fastener24d to a collar 24c from which depend the above-noted rods 23 whichextend downwardly through block 63 (see FIG. 5 and are connected to thepins 171).

The angular disposition of the part 24 relative to the upper housingsection 30 thus determines the relative axial disposition of the stoprings 1-72 in the lower housing section 37. In this manner in theextreme lowermost position of axial adjustment, rings 17e will bedisposed for engagement of stop shoulders 275 through 275e by thependulum 16, but in the event that the instrument is to be adjusted fordetection of angular deviation ranging between say 3 /2 and 7 degrees,if shoulders 275 through 2752 represent detection of angles rangingbetween to 3 /2 degrees, the part 24 may be adjusted to move the stopshoulders upwardly so that a second set of stop shoulders 375 through375] may be disposed for engagement by the pendulum 16. It will also beunderstood that the range of adjustment of the stop shoulders providedby rings 17:: may be such that any combination of stop shoulders 275athrough 375 may be availed for the purpose of detecting angulardeviation within any selected range of the maximum range for which theinstrument is adapted by provision of stop rings 17:; of differentdiameters.

In order to fix the selected range, the rods 23 are provided with aseries of axially spaced depressions 23a with which engage detent means23b which, in the illustrative embodiment, comprises a spring ringdisposed about the block 63 in a groove 230, as best seen in FIG. 5. Onthe upper housing section 30 is fixed, as by fastener 30a (FIG. 2b), acollar 30!; having a suitable index means 30c which, in relation tograduations 30d on the upper end of the rotatable part 24, will serve toindicate the relative axial disposition of the stop ring support sleeve17a within the lower housing section 37. By virtue of this construction,the instrument may be preset so as to detect angular deviation rangingfrom 0 degree deviation through any selected range of the entirecapability of the instrument. For example, either from 0 to 3 /2 degreesor 2 degrees to 5% degrees, etc.

In use, the instrument as described above operates so as to indicate tothe person controlling the progression of a well drilling operation theangle at which the drill collar string immediately above the drill bitis disposed each time the driller stops the drilling operation so thatan additional length of drill pipe may be added to the drill string.This indication is derived inherently due to the fact that thecirculation of drilling fiuid is temporarily arrested. During the periodthat such circulation is halted, the shaft 13 and the knob 14 will moveupwardly through a number of pulse rings representative of the angulardisposition of the drill collar S above the drill bit. In addition, ifthe driller so desires he may intermittently halt the circulation ofdrilling fluid so as to derive, at will, an indication of the angulardisposition of the drill string above the drill bit.

Upward movement of the knob 14 is limited by engagement of the shaftstop 77 with the stop ring 75 on tube 62 or with one of the sets ofballs 75a through 75 depending upon which of the stop shoulders of thestop means 17 has been engaged by the pendulum 16. Therefore, uponresumption of the circulation of drilling fluid the knob 14 will movedownwardly through a number of the pulse rings 7 representative of theincrements of angular deviation, so that pressure signals will beinduced in the stream of drilling fluid to be detected by surfacepressure gauge or surface pressure recorder means to indicate to thedriller the angular disposition of the drill string above the drill bit.At the point in this operation at which the circulation of drillingfluid is arrested and the upward movement of the shaft 13 is arrested byengagement of the stop shoulder '77 with the selected balls 75a through75 the latch means will have been released and the pendulum will be onits seat, but upon resumption of circulation of drilling fluid thedownward movement of the shaft 13 and the resultant downward movement ofthe coding rod 60 will cause the latch means to again be engaged withthe pendulum connecting rod 90, providing that the coding rod 60 movesdownwardly a sufficient distance to assure that the latch finger 98 willreengage the latch shoulder 94, as shown in FIG. 4. The forces resistingsuch downward movement of the coding rod 60 and the latch means 95include the opposing force of the spring 110 within the pendulumconnecting rod which urges the latch body upwardly, the spring 60awithin the coding rod guide tube 61 which acts upwardly on the codingrod, the main spring IE5 and the spring 70b interposed between the upperend of the coding rod 60 and the shaft 13. Therefore, in order to becertain that sufficient downward force on the knob 14 is provided inresponse to the pressure difference acting on the knob 14, the abovedescribed replaceable bushing A is selected to provide a diameter of thewall 5 therefor which will cooperate with the outer periphery of theknob 14 to provide an annular gap or flow passage 5i related to theproposed rate of drilling fluid flow in the drilling operation. Wherelarge drilling fluid flows are to be employed, the diameter of the wall5 of the replaceable bushing A therefore may be larger than when thedrilling operation will involve low fluid flow volume. In thisconnection, the bushing may be selected and installed in the pulse ringtube support 5 so as to provide a flow path or gap 5i which has a lesserarea than the flow area provided between the pulse rings 7 which must belarge, as compared with the flow area defined between the knob 14 andthe pulse rings 7, if discrete pressure pulses are to be produced in thestream of drilling fluid which can be readily distinguished by recordinginstruments at the earths surface.

I claim:

1. In a signalling apparatus adapted to be installed in a well drillingstring for producing pressure signals in a stream of well drilling fluidindicative of the disposition of the drilling string in a well bore,said apparatus comprising: an elongated housing, a shaft having a freeend projecting from an end of said housing, biasing means in saidhousing for moving said shaft from an inner position longitudinallyoutward with respect to said housing, cooperable gravity responsivemeans and stop means spaced longitudinally in said housing for limitingsuch movement of said shaft, said free end of said shaft having asurface responsive to the flow of drilling fluid for moving said shaftinwardly with respect to said housing against said biasing means,pressure pulse producing means for producing said signals during inwardmovement of said shaft, means releasably connecting one of saidcooperable gravity responsive means and stop means to said shaft forreleasing said one of said cooperable gravity responsive means and stopmeans from said shaft responsive to engagement of said gravityresponsive means with said stop means during outward movement of saidshaft, means for limiting outward movement of said shaft upon release ofsaid one of said cooperable gravity responsive means and stop means, andmeans for providing a greater force on said shaft to cause inwardmovement of said shaft during the last stage of its movement toward saidinner position than the force applied to said shaft to move said shaftinwardly during production of said signals.

2. Signalling apparatus as defined in claim 1, wherein said means forproviding a greater force on said shaft comprises means providing arestricted flow path past said surface for the passage of well drillingfluid for increasing the differential pressure acting on said surface tomove said shaft to said inner position.

3. Signalling apparatus as defined in claim 1, wherein said means forproviding a greater force on said shaft comprises means providing arestricted flow path past said surface for the passage of well drillingfluid for increasing the differential pressure acting on said surface tomove said shaft to said inner position, and said means for releasingsaid one of said cooperable gravity responsive means and stop meanscomprises a member carried by said one of said cooperable gravityresponsive means and stop means and a member carried by said shaft, ashoulder on one of said members, a latch carried by the other of saidmembers and engageable with said shoulder, and means for disengagingsaid latch from said shoulder.

4. Signalling apparatus as defined in claim 1, wherein said means forreleasing said one of said cooperable gravity responsive means and stopmeans comprises a member carried by said one of said cooperable gravityresponsive means and stop means and a member carried by said shaft, ashoulder on one of said members, a latch carried by the other of saidmembers and engageable with said shoulder, and means for disengagingsaid latch from said shoulder, and said means for limiting outwardmovement of said shaft comprises further stop means on said latch andsaid housing for limiting outward movement of said shaft upondisengagement of said latch from said shoulder, and said biasing meansincluding spring means acting to separate said latch from said shoulder.

5. Signalling apparatus as defined in claim 1, wherein said means forproviding a greater force on said shaft comprises means providing arestricted flow path past said surface for the passage of well drillingfluid for increasing the differential pressure acting on said surface tomove said shaft to said inner position, and aid means for limitingoutward movement of said shaft includes coding means for limiting saidmovement in inverse relation to the extent of relative movement of saidgravity responsive means and stop means, said biasing means including aspring in said coding means acting to urge said shaft outwardly.

6. Signalling apparatus as defined in claim 5, wherein said coding meansincludes a coding rod, and a plurality of axially spaced shaft stopscooperative with said shaft and said coding rod for limiting saidoutward movement of said shaft in said inverse relation, said springbeing interposed between said coding rod and said shaft.

7. Signalling apparatus as defined in claim 1, wherein said means forlimiting outward movement of said shaft includes coding means forlimiting said movement in inverse relation to the extent of relativemovement of said gravity responsive means and stop means, and said meansfor releasing said one of said cooperable gravity responsive means andstop means includes means releasably connecting said coding rod to saidone of said cooperable gravity responsive means and stop means, andincluding a spring acting to separate said coding rod and said one ofsaid cooperable gravity responsive means and stop means.

8. Signalling apparatus as defined in claim 1, wherein said shaft has aknob at its outer end having said surface thereon, and said means forproviding a greater force on said shaft comprises means cooperative withsaid knob and providing a restricted flow path past said knob forincreasing the differential pressure acting to move said shaft to saidinner position.

9. Signalling apparatus as defined in claim 1, wherein said shaft has aknob at its outer end having said surface thereon, and said means forproviding a greater force on said shaft comprises a bushing having anopening for receiving said knob as said shaft moves inwardly to formwith said knob a restricted flow path past said knob for increasing thedifferential pressure acting to move said shaft to said inner position,and means replaceably supporting said bushing in the path of drillingfluid flow past said knob.

References Cited UNITED STATES PATENTS 3,176,407 5/1965 Alder. 1,905,2995/1933 McLaughlin.

LEONARD FORMAN, Primary Examiner F. J. DAMBROSIO, Assistant Examiner

